Response evaluation by endoscopy, rebiopsy, and endoscopic ultrasound does not accurately predict histopathologic regression after neoadjuvant chemoradiation for esophageal cancer

Abstract

Objective: To prospectively assess the sensitivity (sens), specificity (spec), positive predictive value (ppv), negative predictive value (npv), and accuracy (acc) for clinical response evaluation by endoscopy, rebiopsy, and endoscopic ultrasound (EUS) to determine histomorphologic regression UICC T-category downstaging after neoadjuvant chemoradiation for esophageal cancer.

Background: Histomorphologic regression is meanwhile established as objective parameter for response and prognosis after neoadjuvant chemoradiation for esophageal cancer.

Patients and methods: Within a prospective observation trial, 80 patients with localized esophageal cancers (cT2-4,Nx,M0) received standardized neoadjuvant chemoradiation (cisplatin, 5-fluorouracil, 36 Gy) and were resected by transthoracic en bloc esophagectomy and two-field lymphadenectomy. Tumor regression was based on the percentage of vital residual tumor cells and classified in 4 categories as reported previously. Evaluation by endoscopy and EUS was performed based on WHO/UICC criteria before starting chemoradiation and before resection and rebiopsies were taken at the time of re-endoscopy.

Results: Histomorphologic response was of significant (log rank) prognostic importance (P < 0.001), whereas clinical response evaluation by endoscopy (P = 0.1), rebiopsy (P = 0.34), and EUS (P = 0.35) was not. The results of the 3 diagnostic modalities to assess histomorphologic regression by endoscopy and rebiopsy UICC ypT-category downstaging for EUS are summarized: Endoscopy: sens 60%, spec 34%, ppv 49%, npv 44%, acc 47%. Rebiopsy: sens 36%, spec 100%, ppv 100%, npv 24%, acc 47%. EUS: sens 7%, spec 79%, ppv 18%, npv 57%, acc 50%.

Conclusions: Histomorphologic regression is an objective response parameter of significant prognostic importance. The diagnostic accuracy of endoscopy, rebiopsy, and EUS is inadequate for objective response evaluation after neoadjuvant chemoradiation and can be omitted for this purpose in the clinical practice.